(1990). Ties and Bonds. Connections, 13 (3) - INSNA

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9 MEETINGS F ebruary 14-18, 1991 . Sunbelt XI : International Sunbelt Social Network Conference . Radisson Bay Harbor Inn, Tampa, Florida . Registration through Jeffrey C. Johnson, Institute for Coastal and Marine Resources, East Carolina University, Greenville, NC 27858 . (919)757-6220. March 13-17, 1991 . Society for Applied Anthropology/American Ethnological Society . Sheraton Charleston Hotel, Charleston, SC . SfAA Business Office, Box 24083, Oklahoma City, OK 73124. (405)232-4902. A pril 4-7, 1991 . Society for Economic Anthropology . Bloomington, Indiana. Indiana University Conference Bureau, SEA Meeting, Bloomington, IN 47405 . May 16-20, 1991 . Third International Network Conference on Interpersonal Relatioships (INPR) . Jumer's Chateau, Normal/Bloomington, Illinois . INPR Conference, Dept of Communication, Illinois State University, Normal IL 61761 . J une 2-6, 1991 . International Sociological Association . University of Missouri, Columbia, MO . Theme: The Globalization of Agriculture and Food Order . Dept of Rural Sociology, UM-C, Columbia, MO 65211 . J une 20-22, 1991. European Network Conference . Sorbonne, Paris . Send 400 francs (200 for students) to Secretariat de la Conference sur l'Analyse des Reseaux Sociaux, LASMAS, IRESCO, 59 = 61 rue Pouchet, 75849 Paris Cedex 17 . Tel: 33-1-40 .25 .10 .03 ; Fax : 33-1-42 .28 .95 .44 J une 20-22, 1991. International Institute of Sociology . Japan. Contact Barry Wellman, Dept of Sociology, University of Toronto, Toronto Canada . J une 25-28, 1991. The Fourth Australian and Pacific Researchers in Organization Studies International Colloquium . Kobe, Japan. Contact : Yoshiaka Ueda, University of Marketing and Distribution Sciences, 3-1 Gakuen-Nishimachi, Nishi-ku, Kobe 651- 21 Japan . August 23-27, 1991 . American Sociological Association Annual Meeting . Cincinnati, Ohio. Contact ASA Executive Office, 1722 N Street NW, Washington, DC 20036 . November 20-24, 1991 . American Anthropological Association Annual Meeting . Chicago Marriott Hotel, Chicago, Illinois . Contact AAA Executive Office, 1703 New Hampshire Ave NW, Washington, DC 20009 . Fall/Winter, 1990 Connections
10 ARTICLE Distribution of Measures of Centrality : Enumerated Distributions of Freeman's Graph Centrality Measures Keiko Nakao University of Southern California Introduction In many areas of network research, the idea of centrality has been considered as one of the most important and intuitive structural characteristics of a network or network actors . In fact, centrality is one of the concepts that was introduced in early literature of network research (Bavelas 1948, Leavitt 1951) . Whether a degree of centralization is described for a network as a characteristic of a system or for network actors as positional measures (e.g ., measures of social integration), the application of centrality concepts are numerous and various measures of structural centrality have been developed in different contexts (e .g ., Coleman et al . 1966, 1982 ; Bonacich, 1972; Laumann and Pappi 1976; Laumann, Marsden, and Galaskiewicz 1977 ; Freeman 1979 ; Galaskiewicz 1979 ; Knoke and Laumann 1982; Marsden 1982 ; Cook, et, al. 1983 ; Berkowitz, 1988) . Freeman (1979) reviewed various measures of centrality from a graph-theoretic point of view and identified three distinct measures : (1) degree-based centrality, (2) betweenness-based centrality, and (3) closeness-based centrality . These measures were distinct in the sense that Freeman related each measure to a different interpretable characteristic of the network . For example, the degree-centrality may be interpreted as an index of its communications activity, where the graph relations between nodes are taken to be communication . The degree-centrality value for a graph, then, indicates the extent to which a single point in the graph dominates it in communications . Likewise, the betweenness-centrality of a point identifies the dependency of the graph on that point for communication; the betweenness-centrality value for a graph indicates the uniqueness of such dependencies within the network . Thus, a high betweenness value points to a potential for the control of a network by a single site or node . Finally, the closeness-centrality of a point reveals the efficiency with which a message from that source can saturate the network . Applied to a graph, closeness-centrality reveals the extent to which the efficiency of communication within a network depends on the source of the messages . The conceptual aspect of these measures are very useful in applying them to situations in which the researchers wish to measure specific attributes of centrality . However, the use of these measures is limited probably because of the lack of knowledge about their behavior . For example, these measures might be used inferentially instead of only descriptively if we knew their individual and joint distributions . Currently, although one may describe the degree of centralization of a given network by computing the theoretically appropriate measure of centrality, one cannot be certain how significant the value is . There are other open issues in the use of the current measures of centrality . First, although there are conceptual differences among the three measures, it is not clear how strongly they will be reflected as differences in the values resulting from calculations . Freeman (1979) notes that the three measures differ in their relative ranking when the values are not extreme . However, not enough is known about the implication of such relative ranking between the measures. What does it imply, in terms of the network structure, to have a large value on one centrality measure while having small values on the others The exemplars of various graph-theoretic centrality values would be useful in order to make a substantive use of the information obtained . Further research is needed that compares these measures empirically (e .g., Bolland 1986) and theoretically in order understand the behavior of the network being measured . Secondly, not enough is known about the relationship between the centrality values and the density of a network . In many situations the number of relationships is susceptible to change by various factors, some of which Connections Volume XIII, Number 3
Page 1 and 2: CONNECTIONS Volume XIII Number 3 Fa
Page 3 and 4: CONNECTIONS EDITORIAL OFFICES : Cen
Page 5 and 6: 4 TIES & BONDS Barry Wellman, Unive
Page 7 and 8: of their managerial problems, were
Page 9: 8 LETTER FROM OXFORD I'm beginning
Page 13 and 14: • Betweenness-based measure of gr
Page 15 and 16: 14 structure is the graph known as
Page 17 and 18: Table 16 1 : Cumulative Probability
Page 19 and 20: 18 Table 3 Critical Values of Graph
Page 21 and 22: 20 0 .26 0 ,2 . - 0 .2 . - 01 - 6 .
Page 23 and 24: 22 U> > o CD = 0 .267 CD = 0 . 1.67
Page 25 and 26: 24 tary associations to form along
Page 27 and 28: 26 two elements, predictability and
Page 29 and 30: 28 dividual human failings with whi
Page 31 and 32: 30 communities relate differently t
Page 33 and 34: 32 ABSTRACTS : Chapters Barthelemy,
Page 35 and 36: 34 Monge, Peter R. and Gerald R. Mi
Page 37 and 38: 36 up of overlapping three-point st
Page 39 and 40: 38 Bates, Robert H . (1990) . Capit
Page 41 and 42: 40 Burt, Ronald S . (1990) . Detect
Page 43 and 44: 42 Conn, Michael K, & Peterson, Chr
Page 45 and 46: 44 est is the the dynamic topology
Page 47 and 48: 46 Faxen, Karl-Olof, & Thore, Sten
Page 49 and 50: 48 Gillis, A.R., & Hagan, John . (1
Page 51 and 52: 50 a coherent framework of service
Page 53 and 54: 52 Kilduff, Martin. (1990) . The in
Page 55 and 56: 54 Litwak, Eugene, Messeri, Peter,
Page 57 and 58: 56 Mizruchi, Mark S . (1990) . Dete
Page 59 and 60: 58 physical environment (e .g., poo
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60 Shelley, Gene Ann, Bernard, H. R
Page 63 and 64:
62 have significantly larger networ
Page 65 and 66:
64 Wellman, Barry . (1990) . The pl
Page 67 and 68:
66 dependency and individual differ
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68 Gordon, Steve. (1990) . Emotions
Page 71 and 72:
70 context of close relationships .
Page 73 and 74:
The International Network for Socia
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(1990). Ties and Bonds. Connections, 13 (3) - INSNA

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